2381-21-7Relevant academic research and scientific papers
Fluorescence enhancement of pyrene chromophores induced by alkyl groups through σ-π Conjugation: Systematic synthesis of primary, secondary, and tertiary alkylated pyrenes at the 1, 3, 6, and 8 positions and their photophysical properties
Niko, Yosuke,Kawauchi, Susumu,Otsu, Shun,Tokumaru, Katsumi,Konishi, Gen-Ichi
, p. 3196 - 3207 (2013)
We have systematically synthesized 1-, 3-, 6-, and 8-alkyl-substituted pyrene derivatives using the latest synthesis methods and investigated the effects of alkyl substitution on the photophysical properties of the pyrene chromophore. Like the trimethylsi
Chromophore quench-Labeling: An approach to quantifying catalyst speciation as demonstrated for (EBI)ZrMe2/ b(C6F5)3?Catalyzed polymerization of 1?Hexene
Nelsen, D. Luke,Anding, Bernie J.,Sawicki, Julie L.,Christianson, Matthew D.,Arriola, Daniel J.,Landis, Clark R.
, p. 7398 - 7408 (2016)
Chromophore-containing quench agents 2 and 3 enable quantitative active site counting and determination of the mass distribution of active catalyst polymeryls by refractive index (RI) and UV detected gel permeation chromatography (GPC) for the polymerization of 1-hexene catalyzed by (EBI)ZrMe2/B(C6F5)3. Time evolution of catalyst speciation data and the time profiles of monomer consumption, end-group generation, and bulk molecular weight distribution data have been analyzed by kinetic modeling to determine rate constants for initiation by insertion of hexene into a Zr?Me bond (ki), propagation (kp), chain transfer to form vinylidene (k1,2) and vinylene (k2,1) end groups, and reinitiation from a Zr?H bond (kr). Unlike previous models that assumed fast catalyst reinitiation, this analysis reveals that kr is considerably slower than kp; catalyst speciation data are critical to making this distinction. This study demonstrates that chromophore quench-labeling with 2 and 3 enables rapid, quantitative analysis of detailed kinetic models for catalytic olefin polymerization reactions using GPC with UV and RI detectors.
Alternative Routes for Reductive Alkylations in Liquid Ammonia and Their Selection via Spectroscopic Evidence
Muellen, Klaus,Huber, Walter,Neumann, Gerd,Schnieders, Christoph,Unterberg, Heinz
, p. 801 - 807 (1985)
A wide range of unsaturated hydrocarbons have been reduced with alkali metals in liquid ammonia and the carbanionic intermediates detected in situ by NMR and ESR spectroscopy.The substrates cluster into three different groups depending on whether they (i) persist as dianions, (ii) are protonated by ammonia to afford monohydro anions, or (iii) undergo further electron transfer/protonation steps to yield polyhydro derivatives.The alternative modes of behavior can be correctly predicted on the basis of the relevant atom localization energies.The spectroscopic findings are extremely helpful in rationalizing the results of reductive alkylation experiments and in controlling the regioselectivity of novel quenching reactions.
Metal-Free Direct Deoxygenative Borylation of Aldehydes and Ketones
Huang, Chia-Yu,Li, Chao-Jun,Li, Jianbin,Qiu, Zihang,Wang, Haining
supporting information, p. 13011 - 13020 (2020/09/01)
Direct conversion of aldehydes and ketones into alkylboronic esters via deoxygenative borylation represents an unknown yet highly desirable transformation. Herein, we present a one-step and metal-free method for carbonyl deoxy-borylation under mild conditions. A wide range of aromatic aldehydes and ketones are tolerated and successfully converted into the corresponding benzylboronates. By the same deoxygenation manifold with aliphatic aldehydes and ketones, we also enable a concise synthesis of 1,1,2-tris(boronates), a family of compounds that currently lack efficient synthetic methods. Given its simplicity and versatility, we expect that this novel borylation approach could show great promise in organoboron synthesis and inspire more carbonyl deoxygenative transformations in both academic and industrial settings.
A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
Feng, Boya,Yang, Yudong,You, Jingsong
, p. 6031 - 6035 (2020/07/10)
Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
Ni-Catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents via C-S bond cleavage
Zhu, Dan,Shi, Lei
supporting information, p. 9313 - 9316 (2018/08/29)
A Ni-catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents, accompanied by the cleavage of the C(aryl)-SMe bond, has been presented. This method is distinguished by its mild conditions and moderate functional group tolerance, such as hydroxyl, halogen, and heterocycles, which should provide a straightforward access to the modification of sulfur-containing molecules.
Synthesis of SAPO-35 molecular sieve and its catalytic properties in the methanol-to-olefins reaction
Li, Bing,Tian, Peng,Li, Jinzhe,Chen, Jingrun,Yuan, Yangyang,Su, Xiong,Fan, Dong,Wei, Yingxu,Qi, Yue,Liu, Zhongmin
, p. 798 - 807 (2013/07/25)
SAPO-35 molecular sieve samples with different Si contents were hydrothermally synthesized using hexamethyleneimine as the template and characterized by XRD, XRF, SEM, MAS NMR, XPS and N2 physisorption. Three SAPO-35 samples were tested as methanol-to-olefins catalysts. After the reaction, the evolution of coke species was investigated over SAPO-35 and SAPO-34 catalysts with similar Si concentrations. A correlation between the cage size of the molecular sieves and the coke species was obtained.
Light-emitting device material and light-emitting device
-
, (2009/04/24)
A light emitting device material containing a pyrene compound of formula (1) and a light emitting device. In formula (1), R1 to R18 are the same or different and are selected from hydrogen, alkyl, cycloalkyl, heterocyclic, alkenyl, cycloalkenyl, alkynyl, alkoxy, alkylthio, arylether, arylthioether, aryl, heteroaryl, halogen, carbonyl, carboxyl, oxycarbonyl, carbamoyl, amino, phosphine oxide and silyl; adjacent substituents among R1 to R18 may be combined with each other to form a ring; n represents an integer of 1 to 3; X is —O—, —S— or —NR19—; R19 is selected from hydrogen, alkyl, cycloalkyl, heterocyclic, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl or amino; R19 may be combined with R11 or R18 to form a ring; Y is a single bond, arylene or heteroarylene; and n substituents among R1 to R10 and any one of R11 to R19 are used for linkage with Y
Characterization of the combustion products of polyethylene
Piao, Mingjun,Chu, Shaogang,Zheng, Minghui,Xu, Xiaobai
, p. 1497 - 1512 (2007/10/03)
Polyethylene (PE) was burned in a tube-type furnace with an air flow at a temperature of 600~900°C. Combustion products were collected with glass wool, glass fiber filter, and XAD-2 adsorbent. The analysis of the products was performed with GC-FID and GC-MSD. At low temperature, hydrocarbons were the major components, while at higher temperature the products were composed of polycyclic aromatic hydrocarbons. With the high performance of the Hewlett-Packard 6890GC-5973MSD, more compounds were identified in comparison with previous studies.
(1-PYRENYL)METHYL CARBAMATES FOR FLUORESCENT "CAGED" AMINO ACIDS AND PEPTIDES
Okada, Shigeto,Yamashita, Senichi,Furuta, Toshiaki,Iwamura, Michiko
, p. 431 - 434 (2007/10/02)
A highly fluorescent 1-pyrenylmethyloxycarbonyl amino acid (Pmoc-amino acid) is obtained in moderate yield by the reaction of (1-pyrenylmethyl)-4-nitrophenylcarbonate with an amino acid in the presence of sodium carbonate.The condensation of Pmoc-amino acid with an amino acid gives Pmoc-peptide in the presence of 1-ethyl-3-(3-dimethylaminepropyl)carbodiimide and 1-hydroxybenzotriazole.The amino acid is recovered from an H2O-dioxane (2:3) solution of Pmoc-amino acid by irradiation through a Pyrex filter with a medium pressure Hg lamp or at 340 nm.Although the quantum yield of the photolysis is rather low (ca 0.01), the photolysis proceeds fast and efficiently due to the large absorption coefficient of Pmoc-amino acid at around 340 nm.Thus, the use of Pmoc-amino acid as a "caged" amino acid is promising.
